Wireless networks are telecommunications networks that use radio waves to carry information from one node in the network to one or more receiving nodes in the network. Cellular telephony is characterized by the use of radio cells that provide radio coverage for a geographic area, with multiple cells arranged to provide contiguous radio coverage over a larger area. Wired communication can also be used in portions of a wireless network, such as between cells or access points. Wireless communication technologies are used in connection with many applications, including, for example, satellite communications systems, portable digital assistants (PDAs), laptop computers, and mobile devices (e.g., cellular telephones, user equipment). Users of such applications can connect to a network (e.g., the Internet) as long as the user is within range of such a wireless communication technology.
Each wireless communication technology has a corresponding radio access technology. In some geographical areas, network connectivity is achieved through a combination of radio access technologies. For example, as a new generation of radio access technologies are made available in an area, a mobile device is likely to receive a mix of service from a new generation radio access technology (e.g., E-UTRAN) and a previous generation radio access technologies (e.g., GERAN/UTRAN), switching between them often. The Idle state Signaling Reduction (ISR) mode, once activated, allows a mobile device to reselect between available radio access technologies with reduced radio signaling.